Refueling system and method

ABSTRACT

An apparatus and method for refueling an aircraft comprising a hose guide. The hose guide includes a framework having wings and remotely-adjustable control surfaces interacting with air through which the hose guide moves. An attachment interface, attaching the hose guide to a fuel hose extended from a tanker aircraft, at a distal end away from the tanker aircraft, and a control system adjusting the adjustable control surfaces. Wherein the hose guide is towed as a glider by the tanker aircraft, and adjustment of the control surfaces adjusts three-dimensional position of the end of the fuel hose at the hose guide relative to position of the tanker aircraft.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is in the technical field of refueling aircraft in flight, and pertains more particularly to a system with operation transparent to the receiver of fuel.

2. Description of Related Art

Refueling aircraft in flight is a well-known process, and there are many examples of systems and equipment in the art provided to accomplish refueling of aircraft. In the systems extant at the time of filing this patent application, to the inventor's knowledge, all such systems require automated or user-directed cooperation of an aircraft being refueled to accomplish the process. For example, in many such systems, a tanker aircraft positions proximate an aircraft to be refueled, and trails a hose for transferring fuel. Typically the hose is dry, meaning that there is no fuel in the hose at the time of seeking connection of the hose to a receiver at the aircraft to be refueled. Personnel on board the receiving aircraft are then responsible for maneuvering the receiving aircraft into a position that the fueling hose may be captured, and connected to receiving equipment. There are many problems associated with this prior art process, not the least of which is, that the receiving aircraft must be diverted from whatever mission it may be conducting to accomplish the refueling process, and then must redirect back to the mission at hand.

What is clearly needed is a system and process in which the receiving aircraft may be refueled without interruption, and transparently to the receiving aircraft, its operating systems, or its operating personnel.

BRIEF SUMMARY OF THE INVENTION

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is an illustration showing a tanker enabled to fuel a second aircraft in an embodiment of the invention.

FIG. 1B is an enlarged view of a miniature flyer for positioning a fuel supply hose in an embodiment of the invention.

FIG. 2 is a an illustration of the tanker of FIG. 1A with hoses extended.

FIG. 3A is a perspective view of a fuel-receiving aircraft in an embodiment of the invention.

FIG. 3B is an enlargement showing a fuel-receiving port on the receiving aircraft of FIG. 3A.

FIG. 4 is a cutaway illustration of elements of a flyer in an embodiment of the invention.

FIG. 5 is a perspective illustration of a flyer, towed by a hose, approaching position to an acquisition blade on a receiving aircraft.

FIG. 6 is a perspective illustration of the flyer and acquisition blade of FIG. 5, with the flyer in position to acquire the blade.

FIG. 7 is a perspective view of the flyer and acquisition blade of FIG. 6, with the roller fairings closed, acquiring the blade with the rollers.

FIG. 8 is a perspective view of the flyer and acquisition blade of FIG. 7, with the flyer lowered to the wing of the receiving aircraft.

FIG. 9 is a flow diagram illustrating step-by-step activity in refueling a receiving aircraft in an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1A is an illustration showing a tanker 101 enabled to fuel a second aircraft in an embodiment of the invention. In various embodiments of the invention a tanker may be characterized as a maneuverable aircraft having fuel tanks within or attached to a body 102, the fuel tanks coupled to supply hoses (104), for providing fuel to receiving aircraft. The tanker aircraft may be piloted, or may be a pilotless drone aircraft controlled remotely, or controlled principally by on-board computer-guided systems, that may be in two-way communication with one or more remote stations that provide periodic or continuous instruction and updates. Tanker 101 is illustrated in FIG. 1A as a single-engine, propeller-driven aircraft, but this is exemplary only, and the tanker may be implemented in a variety of different configurations.

A necessary characteristic of tanker 101 in embodiments of the invention is that there is at least one extendable/retractable fuel hose 104 coupled to a fuel-supply tank, for providing fuel to a receiving aircraft. Another necessary characteristic is that the fuel-supply hose terminates at an end away from the tanker aircraft at a miniature flyer 103, that, by virtue of remotely-operable control surfaces, is capable of manipulating in space to a limited degree, to position the end supply end of the fuel hose, while the hose is extended in a fueling operation. The flyer serves as a hose guide. In various embodiments one tanker aircraft may have one, two, or even more extendable/retractable fuel hoses, with flyers coupled at the ends of the hoses away from the tanker aircraft.

FIG. 1B is an enlarged view of the miniature flyer 103, shown in a different attitude than shown in FIG. 1A, and coupled to extendible/retractable hose 104. Miniature flyer 103 has essentially all of the systems of an independently-functional aircraft, except for an independent propulsion system. The propulsion system of flyer 103 is the force applied by hose 104 coupled substantially at the center-of-gravity of the flyer.

Flyer 103 is a glider towed by tanker 101. Gliders are good examples of unpowered aircraft. When a glider is towed to altitude, thrust is derived from the aircraft towing the glider, through whatever tether connects the towing aircraft and the glider. Some of the horsepower provided by the towing aircraft is used to drive the glider through the air.

Flyer 103 in this example has elevators 105, ailerons 106, rudder 107 and speed brakes 108 to rotate the aircraft through the three axis of rotation namely pitch (elevator), roll (ailerons) and yaw (rudder), and to slow and speed up the flyer as needed. All rotations act through the center of gravity of the aircraft. In the flyer, the hose, in one embodiment, attaches to a ball swivel 110 located at the center of gravity of the flyer. An additional component of flyers in an embodiment of the invention is one or more imaging apparatus, such as video cameras 109. The use and significance of cameras 109 is described in further detail below.

Maneuverability of the flyer is a very important feature of the system, because it allows the flyer to move up and down via the elevator, side to side via the ailerons and rudder and forward and back via the speed brakes. Even though the flyer will point upward when the elevator pitches it up, the end of the hose at the center of gravity simply moves up, rather than pointing in a different direction. Likewise, when the flyer rolls or rotates sideways via the rudder, the end of the hose simply translates. All that is needed is for the end of the hose to move back and forth, up and down and side to side. This is all accomplished without independent power, as the flyer is towed by the tanker aircraft.

FIG. 2 is a an illustration of tanker 101 similar to the tanker of FIG. 1A, with two hoses extended from reels (not shown), within the body of the tanker, each hose having a flyer 103 attached at the terminal end, stabilizing and directing the end of the hose. In operation other than refueling, the flyers 103 are carried in a secure location on the tanker, as shown in FIG. 1A, with the fuel hoses retracted. The hoses extended with the flyers deployed, as shown in FIG. 2, is only when the tanker has positioned relative to a receiving aircraft in a refueling operation.

FIG. 3A is a perspective view of a fuel-receiving aircraft 301 in an embodiment of the invention. As was explained relative to the tanker aircraft, although receiving aircraft 301 is illustrated as a single-engine, single-wing aircraft, the receiving aircraft may be any of a broad variety of aircraft, piloted, or drone-operated pilotless. The depiction of FIG. 3A is exemplary only. One or more fuel-receiving apparatus 303 is implemented on a wing 302, in this example, of the receiving aircraft. In other embodiments the receiving apparatus might be implemented elsewhere than a top surface of the wing.

FIG. 3B is an enlargement showing the fuel-receiving apparatus 303 on a portion of wing 302 of receiving aircraft 301 of FIG. 3A. The receiving apparatus comprises an aerodynamic acquisition blade304 extending a significant height above the wing, as shown, with the leading and trailing edges aligned in the direction of flight of the receiving aircraft. A fuel-receiving port 305 is implemented at top of acquisition blade 304, and although not explicitly illustrated, is connected to the fuel tank or tanks of the receiving aircraft. Port 305 is implemented in a manner to be automatically coupled to and sealed to an end of a hose 104 carried by a flyer 103, in a coupling operation described more fully below.

A necessary operation in refueling a receiver in an embodiment of the invention is an operation of locating blade 304 and port 305 by an approaching flyer 103, carrying a donor end of hose 104. With flyers 103 configured to fly a level course, and hoses 104 deployed a specific distance, the spatial relationship of the flyer to the tanker is a known relationship. In embodiments of the invention, in a perfect world, the tanker might be positioned in exactly this relationship to the receiving aircraft, and the flyers might dock with the blades. But there are far too many variables for this to be a practical operation.

In embodiments of the invention, flyers 103 have cameras 109 implemented to capture images, preferably at a rapid video rate, of objects in their immediate vicinity. In the present example, cameras 109 are implemented in transparent bubbles on the end of wings of flyer 103, as seen in FIG. 1B. In some embodiments cameras may also be implemented on ends of rear stabilizer wings of the flyer. Multiple cameras with known spatial relationships provide for efficient computation in location operations. Also in embodiments of the invention, machine intelligence may be implemented in the flyer, in the tanker, or partially in both. In one implementation, computer code may be provided and executed that allows the cameras to seek and identify blade shapes, like blade 304 on a wing of the receiving aircraft. This, however, is a computationally intensive operation.

In one embodiment of the invention, indicia are provided on or near blade 304, the indicia sought and acquired by the cameras, and from known spatial relationships of indicia to blade, the machine intelligence in cooperation with the acquired images of the cameras, may be executed to operate the elevators 105, ailerons 106, rudder 107 and speed brakes 108 of the flyer, to cause the flyer to approach the blade on the receiving aircraft, and to position and engage the blade, to connect hose 104 to port 305, and to supply fuel to the receiving aircraft.

FIG. 3B shows indicia 306, affixed to an upper surface of wing 302, at a known dimension from blade 304. There are different candidates for indicia 306. In one embodiment of the invention indicia 306 are what are termed AprilTags. AprilTag is a visual fiducial system, known in the art, useful for a wide variety of tasks including augmented reality, robotics, and camera calibration. AprilTag targets may be created from an ordinary printer, and the machine-coded AprilTag detection software computes the precise 3D position, orientation, and identity of the tags relative to the camera.

Implementations of AprilTag software are available in Java, as well as in C. Notably, the C implementation has no external dependencies and is designed to be easily included in other applications, as well as portable to embedded devices. Real-time performance can be achieved even on cell-phone-grade processors. The AprilTag fiducial design and coding system are based on a near-optimal lexicographic coding system, and the detection software is robust to lighting conditions and view angle.

A refueling operation, practicing principles of the present invention, may proceed in a variety of ways, and under a variety of circumstances and conditions. In all cases there will be a tanker aircraft to supply fuel, and a receiver aircraft to be fueled. The tanker may have widely variable characteristics, and may be either piloted or unpiloted, remotely controlled or self-controlled. In all cases a commonality is that the tanker will have at least one extendable/retractable fueling hose, in many cases manipulated by a reel mechanism, and a flyer as shown generally as element 103 in FIGS. 1A and 1B will be coupled at the fueling end of the hose. The receiving aircraft will have at least one of the blades 304 implemented on a surface, such as a wing, in a position where the blade may be accessed by the flyer.

Acquisition is done in stages. Firstly, the tanker, which is the aircraft that carries the flyer to the receiving aircraft, flies to a pre-determined position based on the known position of the receiver. The location of the receiver is known by flight plan, GPS or visual systems, or by a combination of these procedures. In a prior art refueling operation, the tanker flies a predetermined and standardized track. With the system in embodiments of the invention, the receiver is flying a predictable and standardized track, which may be a Combat Air Patrol or CAP. A CAP is usually a circular path at constant altitude that takes, in one example, about four minutes to complete. Four minutes to make a 360 degree turn is called a standard rate turn. The receiver doesn't have to be in a standard rate turn for the system and procedure of the invention to be practiced, but if intelligence directing the tanker knows the path size and duration of the receiver, whether standard or not, the tanker can be directed to a position where the receiver will be when the tanker arrives. Global Positioning Systems (GPS) and very accurate navigational computer algorithms may compute the relative positions of the tanker and the receiver, and may fly the tanker to a rendezvous well within a meter of a destination point in three axes. With the two aircraft sharing data via radio link or some other means of direct communication, the locations and rendezvous trajectories may be enhanced.

In an important embodiment of the invention, the entire operation may be transparent to the receiving aircraft, except for the addition of fuel, for the weight of which the receiver aircraft may automatically adjust power and navigation to maintain a planned operation. In this example, the receiver does not maneuver relative to the tanker, but simply continues to fly a pre-planned mission. The receiver is passive in the operation.

The tanker maneuvers to a position above and in front of the receiving aircraft. The flyer, or multiple flyers, will stabilize at a certain position below and behind the tanker, with control surfaces stabilized. The destination position for the tanker is therefore this known spatial offset. If the tanker could fly accurately enough, the flyer would not be necessary. That accuracy in the acquisition operating is not realistic, so the final stage of a rendezvous and contact is accomplished with fine maneuvering by the flyer.

This final positioning may be done in different ways. For example, a two-way data link between the two assets may periodically share precision GPS data, and with such updates, the flyer may be directed to the refueling blade, which may be on the top of a wing of the receiving aircraft. This technology is called Real-Time-Kinematics (RTK), and is used by many industries to get precision location data down to a cm level. But with RTK the tanker and receiver have to talk to each other. A goal of the invention is to have the receiver do as little as possible.

In one embodiment of the invention a video camera vision system, sometimes termed computer vision (CV) or machine vision (MV), is used to guide final positioning. CV can locate and map objects to mm accuracy. A crude CV system can locate the receiver from a mile away without difficulty and can discern objects on the aircraft, such as the refueling receptacle, or AprilTags, from 500 ft on in.

So in one embodiment a CV system using cameras, such as cameras 109 in FIG. 1B, may be used in conjunction with executing software in a processor in the flyer or the tanker, to do final positioning. Training the system to look for objects shaped like blade 304 is one option, but this will challenge a processor, because the process is computer intensive.

FIG. 4 illustrates a flyer 103 according to one embodiment of the invention, shown in partial section, to illustrate elements of the flyer that are associated with connection of the flyer and the hose carried to a receiving port on a receiving aircraft. In this example the hose is not shown, but connects to the flyer at the ball swivel 110 shown in FIG. 4, and described above, located at the center of gravity of the flyer. Below ball swivel 110 there is a vertically-translatable valve 401 in a vertical fuel passage through the body of the flyer. This valve, when the flyer is not coupled to a receiving port is normally seated in a valve seat 402, and held thus either by spring tension, or by pressure in the fuel line, or both. The valve has a valve stem 403 guided through the center of seat 402. This stem encounters a triggering element in a port in an acquisition blade as the flyer lowers to the receiver, and opens the valve at the proper time.

In embodiments of the invention, flyer 103 has two roller clamp fairings 407 (one shown in FIG. 4), that have each a powered, curved roller 406. These fairings each carry a controllable electric motor to drive the roller, and the fairing connect to the flyer by a strut 408 that may be rotated relative to the body of the flyer, to move the rollers toward one another until they clamp onto the acquisition blade, and then roll to pull the flyer down until a seal 404 encounters port 305. The process of acquiring an acquisition blade on a receiving aircraft, and docking the hose to a port is described in further detail below.

FIG. 5 illustrates a flyer 103, carrying a fuel hose 104 from a tanker, approaching an acquisition blade 304 implemented on a wing 302 of a receiving aircraft. Blade 304 has a receiving port 305 for hose 104, and there are two AprilTags 306 placed on wing 302 in a known relationship to blade 304, as described above with reference to FIG. 3. The tanker from which the fuel hose trails is not shown in FIG. 5, but the tanker and the flyer each have circuitry, including two-way wireless communication, for sharing information and coordinating actions in the process of causing the flyer to acquire acquisition blade 304, and to engage the fuel hose to fueling port 305 at the top of the acquisition blade.

FIG. 6 is a perspective illustration of the flyer 103 and acquisition blade 304 of FIG. 5, with the flyer in position to acquire the blade. In FIG. 6, the control circuitry and processor in the flyer, has acquired positioning information by image capture of one or both AprilTags 306, and has operated the elevators 105, ailerons 106, rudder 107 and speed brakes 108, as necessary to maneuver the flyer so that the hose attachment to the flyer is directly over port 305, and the flyer is at a distance above wing 302 such that the roller fairings (407, FIG. 4), may be rotated together such that the rollers may contact acquisition blade 304 from each side.

FIG. 7 is a perspective view of the flyer 103 and acquisition blade 304 of FIG. 6, with the roller fairings 407 closed, acquiring the blade with the rollers. With the blade thus acquired by the rollers, which may be sensed by sensors in the drives for moving the struts to close the fairings, the flyer is at this point joined securely to the acquisition blade, and the rollers may be started to lower the flyer until seal 404 (see FIG. 4) engages port 305 securely. It may be noted that the curved nature of the acquisition blade and the rollers in the roller fairings of the flyer provide a final positioning resource for the engagement of the flyer and the blade, such that, if the flyer is a bit off, the closing of the fairings to press the blades against the blade will move the flyer into final, and perfect, position.

FIG. 8 is a perspective view of the flyer and acquisition blade of FIG. 7, with the flyer lowered to the wing of the receiving aircraft by operation of the rollers in the roller fairings of the flyer, and engagement of seal 404 (FIG. 4) with port 305 at the top of the acquisition blade. With seal 404 engaged securely with port 305, fuel may be safely transferred.

Referring now to FIG. 4, it may be noted that valve stem 403 is of a length that it extends below seal 404. Therefore, with seal 404 engaged in port 305, stem 403 may extend into port 305 in acquisition blade 304. In one embodiment of the invention there may be an actuator to contact stem 403 to lift valve 401 from seat 402. In embodiments of the invention wherein fuel hoses 104 are pressurized with fuel, even while the hoses are extended and retracted, and before engagement with an acquisition blade, this actuation will immediately start flow of fuel into tanks of the receiving aircraft. In another embodiment there may be an electromechanical actuator to operate valve 401, in which case, once the flyer senses that seal 404 is seated in port 305, the actuator may be triggered to begin fuel flow.

It is important to note that fuel tanks on typical aircraft are not designed and manufactured to withstand a great deal of internal pressure. Fuel tanks in most aircraft, in fact, may withstand only a nominal internal pressure before failing. In view of the fact that a tanker aircraft, in an embodiment of the invention, will necessarily have to fly at a significant altitude above that of a receiving aircraft, if the flyer were to join the fuel hose to a fuel tank of a receiving aircraft in a liquid and airtight manner, the pressure head of the fuel at the acquisition blade and in the tanks of the receiving aircraft would be far above any safe pressure to which the tanks should be subjected. For this reason, fuel tanks in the receiving aircraft are vented, and the fuel system including the fuel hose during fuel transfer is also vented.

Referring again to FIG. 4, element 405 is a seal over a vent channel in the flyer. A sensor, not shown, will sense fuel at the vent, indicating that the tanks of the receiving aircraft are full, and the control systems will stop the fueling process. In one embodiment this simply involves activating the rollers in the roller fairings to lift the flyer from the wing of the receiving aircraft, which allows valve 401 to close at or before the point that seal 404 unseats from port 305.

When the receiving aircraft tank or tanks are full, or when a pre-programmed quantity of fuel has been transferred, disengagement may begin. There are a variety of ways in different implementations that the fact of sufficient fuel transfer may be known. As it is an object of the invention that the refueling operation may be transparent to a receiving aircraft, the end of the fueling operation is sensed by the flyer. In one embodiment the flyer may meter fuel flow. In another embodiment, the fuel transfer may be a timed operation. In most embodiments, fuel at a vent is detected, as described above.

When fuel transfer is complete, disengagement is, in early steps, a reversal of the final steps of engagement. Once transfer is finished, the rollers in the roller fairings of the flyer are operated again in the reverse of the rotation for engagement, raising the flyer from the position of FIG. 8, until seal 404 breaks contact with port 305. In an embodiment wherein valve 401 is opened by a mechanical contact with stem 403, pressure in the fuel line will close the valve as contact is broken. In an embodiment wherein an electromechanical actuator closes the valve, this may be triggered by sensing when contact is about to be broken.

Once contact is broken, and valve 401 is closed, the flyer may rotate the struts to open the rollers from the acquisition blade, and the flyer is then free of the receiving aircraft. The flyer at this point may signal the tanker aircraft, or the tanker aircraft may sense the condition, and the tanker aircraft may proceed to retract hoses 104, and may proceed on a further mission for refueling another receiving aircraft, or may return to a base to be replenished with fuel for further missions.

In exemplary embodiments of the invention, as described above, the entire operation may be transparent to the receiving aircraft, which simply continues with its mission. It is, however, necessary that the control systems in the tanker aircraft, and perhaps to some extent in the flyer(s), are aware of the mission of the receiving aircraft, and its geographic location and course, and especially of any alterations in the course of the receiving aircraft. It is preferable, and in some cases required, that the refueling operation be carried out while the receiving aircraft is flying a straight and level course.

FIG. 9 is a flow diagram illustrating step-by-step activity of a tanker having one or more fuel hoses and flyers at the end of the hoses, according to an embodiment of the invention, in a refueling operation. At step 901 tanker aircraft loads a mission plan and data. The plan will identify a receiving aircraft to be refueled, and the data will include the location geographically of the receiving aircraft (GPS), and details of the mission and flight activity of the receiving aircraft.

At step 902 the tanker aircraft vectors to the known position of the receiving aircraft. This, of course is done by calculating where the receiving aircraft will be according to details of its mission and flight plan. When the tanker arrives in the proximity of the receiver aircraft, at step 903 the tanker extends its fuel hose or hoses to a predetermined extent. Each hose has a flyer at the end, with flight apparatus set to a level and steady flight for the end of the respective fuel hose.

Once the hose or hoses are fully extended, the tanker aircraft in step 904 maneuvers to bring the flyers at the ends of the hoses closer to acquisition apparatus on the receiving aircraft. During this operation the image acquisition system of the flyer or flyers, looks for indicia to acquire positioning data. At step 905 the control systems query for acquisition of indicia. If indicia are not acquired, control goes to step 906, and the tanker aircraft continues to close the distance to acquire indicia.

When indicia are acquired, at step 907 the tanker flight is stabilized, and the flyers, having uploaded data provided by the indicia, at step 908 operate flight apparatus to close to a position where the flyer may acquire an acquisition blade by the rollers in the roller fairings. The controls periodically or continually check, and the flyers continue to maneuver, until at step 909, the a flyer is in position, and signals to close the rollers on the acquisition blade. If there is more than one hose and flyer, the closure may be at a different point for each flyer and blade. The rollers are operated at step 910 to lower the flyer(s) to engage seal 404 with port 305.

When seal is accomplished, fuel is transferred at step 911. After fuel transfer is sensed as complete, the fuel valve in the flyer is closed at step 912, and the rollers are reversed to disengage the seal from the port at step 913. At step 914 the rollers are released from the blade, freeing the flyer(s) from the receiving aircraft, and at step 915 the tanker retracts the hoses, and exits to any further mission.

The application of a flyer to manipulate the end of a fuel hose extended from a tanker aircraft, as described in embodiments above, is but one application of practice of the present invention. Other applications are described in following paragraphs.

As a prelude to further, and broader, application of practice of the invention, consider that flyer 103 in the embodiments described thus far is in essence an unpowered glider, towed by the tanker aircraft by the fuel hose. In a more abstract sense, the flyer is a mobile end affecter for providing limited maneuvering to an end of a supple, that is, limber, tether, which is a fuel hose in the embodiments described above in enabling detail. Operating the maneuvering apparatus of the flyer enables the end of the hose to be precisely placed to a fuel port of a receiving aircraft.

Operation, strictly as a glider is feasible in many practices of the invention, but in some applications, the flyer may be powered, and the power may be by conventional propeller(s), or may be by thrusters, such as jet, rocket, or turbine operation. In some embodiments the conventional ailerons, etc., described with reference to FIG. 1B, for example, may not be necessary at all, as all maneuvering, as well as powered flight, might be provided by directional thrusters.

Powered flight by an end affecter will be desirable in applications where a limber tether is used from such as a helicopter. Consider, for example, rescue situations where a helicopter may be used with a harness to reach and reel in a person stranded on a face of a cliff In traditional operation the helicopter lowers (extends) a tether with a harness, or a person and a harness, the person to help in applying the harness to a subject. Suppose the cliff face has a negative slope and/or an overhang, such that the subject is not in line of vertical sight from the helicopter. If a powered end affecter is incorporated at or near the end of the tether, and is controllable from the helicopter, the lower end of the tether may move under an overhang, for example, and deliver the harness to a person that could otherwise not be reached.

In another circumstance, a subject might be in line of sight from the helicopter, but turbulence and prevailing wind may make it very difficult to deliver the end of the tether where wanted. Having a powered end affecter, and ability to control same, may make such a rescue operation more efficient, and result in a higher success rate.

In circumstances wherein a destination point for and end of a tether, or other flexible conduit or hose, might be obscured from sight of an operative on an aircraft, as in the case of guiding a harness on a tether to a person isolated on a cliff, for example, the tether might include one or more data lines by which a video camera or other imaging device at the end affecter might provide a display to the operative in the aircraft. The operative, by virtue of the control system and imaging device could fly the end affecter with the harness right to the person needing the harness for rescue. There are many other applications for such a remotely-controllable end affecter with video sight capability.

In another application, a tether may not be a fuel hose, but, for example, a data cable. There may well be applications in which a providing aircraft, or even a satellite or a space voyager, may collect large quantity of data. Consider, for example, video camera operation for mapping, or for simply collecting a great deal of information. Wireless transfer may be considerably slower than collection, resulting in backup of data. A collecting vehicle might extend a tether, comprising a data cable, and a flyer or other end affecter at the end of the tether, might operate, as in the fueling operation, to connect to a receiving aircraft, for a hard-wired transfer of large amounts of data quickly.

In one circumstance, a glider might be utilized as transport for cargo or people, or both. If the transporter is not directly powered, it need not be refueled. Some way is needed, however, to keep the glider aloft and moving toward a planned destination. In one embodiment a powered towing aircraft might be provided with an extendable/retractable towing tether having a mobile end affecter, such that the tether may be extended, and may hook up to the glider transparently to the glider. The towing aircraft need not have cargo capability, and may be designed for efficiency as a towing unit. In some embodiments the towing aircraft may disconnect when its own fuel runs low, and a hand off to a second, or a next, towing aircraft, in a relay. At a destination the glider may be cut free to glide to a safe landing, either guided by an on-board pilot or by automatic systems. Alternatively, the glider might be guided in to land while still attached by tether to a towing aircraft. In this latter case, the tether may include communication and data cables through which control circuitry in the towing aircraft may operate apparatus and control systems in the glider.

In the circumstance of towing a glider, carrying either cargo or people, or both, there may be a plurality of towing aircraft, and a plurality of attachment points and apparatus on the glider where towing aircraft may attach and detach. Tethers from the towing aircraft may have end affecters much like the flyers described above, or having alternative apparatus, such as thrusters, to accomplish necessary maneuvering about the three axes around a center-of-gravity, to seek, find, and accomplish attachment to physical points of engagement to affect towing. The end affecters in this circumstance may have imaging devices, and there may be target indicia affixed to surfaces on the glider, for acquisition by the end affecters to home in on attachment points.

There are many other applications for end affecters for otherwise limp tethers, hoses and communication lines. In a further example, fire hoses, used by firefighters, might benefit from such end effecters. Fire hoses with video capability and flying end affecters may be deployed at a fire to take the end of a fire hose into a window or through a doorway, to be moved within a burning structure to a point of maximum effect, before water, foam or fire retardant may be ejected from the hose. In some cases intermediate flyers might be joined to a hose at points along the hose to support the hose as the end affecter flyer carries the end of the hose.

In yet another potential application of embodiments of the invention, it is known that an object, suspended by a lengthy tether from a fixed wing aircraft, may maintain, at the altitude of the object, a relatively stable fixed position, if the fixed wing aircraft were to fly a circular course at a speed and at a radius that just compensates for the pendulum motion that the object would exhibit at any moment as tethered to the aircraft. This is simply a problem in math, with the weight of the object known, and the weight and nature of the tether known.

In such a situation, and end affecter as described in many embodiments herein might be used to correct for discrepancies such as wind variables, etc., and a fixed wing aircraft could then be employed in many applications which otherwise belong to helicopters, drones, and other aircraft capable of hover operation.

In still another operation, a weapon pod might be suspended from either a fixed wing aircraft, as described just above, or from a hover craft, with an end affecter that could translate the pod in essentially an X/Y plane, to position the pod, capable of dropping grenades and the like, precisely over targets.

It will be apparent to the skilled person that the implementations illustrated and described in this application are exemplary only, and not limiting to the scope of the invention. There are many variations that may be made in the examples described, all within the scope of the invention. For example, tanker aircraft may take many and varied forms, and fuel hoses may be extended and retracted in a variety of ways. Flyers may also be employed in various sizes and configurations, and not all will have the same maneuvering apparatus. Control circuitry and apparatus will vary, as well, and may be computerized in a variety of ways. There are many other alterations that might be made within the scope of the invention, and the invention may be practiced incorporating any or all of the examples described, singly or in combination. The invention is limited only by the scope of the claims that follow. 

1. A hose guide, comprising: a framework having wings and remotely-adjustable control surfaces interacting with air through which the hose guide moves; an attachment interface, attaching the hose guide to a fuel hose extended from a tanker aircraft, at a distal end away from the tanker aircraft; and a control system adjusting the adjustable control surfaces; wherein the hose guide is towed as a glider by the tanker aircraft, and adjustment of the control surfaces adjusts three-dimensional position of the end of the fuel hose at the hose guide relative to position of the tanker aircraft.
 2. The hose guide of claim 1 wherein the fuel line connects to the framework at center-of-gravity of the framework, and the framework further comprises a remotely-operable valve through which fuel from the fuel line must pass, allowing the fuel line to be towed full of fuel.
 3. The hose guide of claim 2 wherein the remotely-adjustable control surfaces comprise elevators, ailerons, a rudder and speed brakes configured to move the hose guide through three axes of rotation.
 4. The hose guide of claim 2 further comprising an engagement interface, including a sealing element, below the framework, enabling the hose guide to engage a matching fueling port on a receiving aircraft.
 5. The hose guide of claim 4 further comprising a digital imaging device, wherein the digital imaging device acquires indicia on a surface of a receiving aircraft, providing information about proximity of the fueling port, and the control system uses the proximity information to manipulate the hose guide to maneuver to dock with the fueling port.
 6. The hose guide of claim 5 wherein docking triggers the valve to open, allowing fuel to flow from the fuel line into fuel tanks of the receiving aircraft.
 7. The hose guide of claim 6 wherein a sensing apparatus senses fuel in a vent, signaling that sufficient fuel is transferred, and the control system manages withdrawal of the hose guide from the fuel port.
 8. The hose guide of claim 5 wherein the fueling port is at a top surface of an aerodynamic acquisition blade having curved sides, and the hose guide further comprises a roller system with electrically-driven rollers curved to mesh with the sides of the acquisition blade.
 9. The hose guide of claim 8 wherein the electrically-driven rollers are articulated to close from opposite sides of the acquisition blade, the control system manages the rollers to lower the hose guide until the fuel line seals to the fueling port and a mechanical trigger opens the valve to start fuel flow into the tanks of the receiving aircraft.
 10. The hose guide of claim 9 wherein, at end of fueling, the control system reverses the rollers to raise the hose guide on the acquisition blade, allowing the fuel valve to close, and disconnecting the fuel line from the fueling port.
 11. A method for refueling a receiving aircraft, comprising: extending a fuel hose from a tanker aircraft, the fuel hose having a hose guide on an end away from the tanker aircraft, the hose guide comprising a framework having wings and remotely-adjustable control surfaces interacting with air through which the hose guide moves, and a control system adjusting the adjustable control surfaces to determine three-dimensional position of the end of the fuel hose at the hose guide relative to position of the tanker aircraft; towing the hose guide by the fuel line to vicinity of the receiving aircraft; acquiring an indicia on a surface of the receiving aircraft, by a digital imaging device on the hose guide, providing information about proximity of a fueling port; and using the proximity information by the control system to maneuver the hose guide to dock with the fueling port.
 12. The method of claim 11 further comprising opening a valve in the fuel line, allowing fuel to flow from the tanker aircraft into fuel tanks of the receiver aircraft.
 13. The method of claim 12 wherein the hose guide is configured as a glider having elevators, ailerons, a rudder and speed brakes configured to move the glider through the three axes of rotation.
 14. The method of claim 12, wherein the docking triggers the valve to open allowing fuel to flow from the fuel line into tanks of the receiving aircraft.
 15. The method of 14 further comprising sensing fuel a vent, signaling that sufficient fuel is transferred, and managing, by the control system, withdrawal of the hose guide from the fuel port.
 16. The method of claim 11 wherein the fueling port is at a top surface of an aerodynamic acquisition blade having curved sides, and the hose guide docks by engaging the acquisition blade with a roller system having electrically-driven rollers curved to mesh with the sides of the acquisition blade.
 17. The method of claim 16 wherein the electrically-driven rollers are articulated to close from opposite sides of the acquisition blade, the control system manages the rollers to lower the hose guide until the fuel line seals to the fueling port and a mechanical trigger opens a valve to start fuel flow into the tanks of the receiving aircraft.
 18. The method of claim 17 wherein, at end of fueling, the control system reverses the rollers to raise the hose guide on the acquisition blade, allowing the fuel valve to close, and disconnecting the fuel line from the fueling port. 